A large number of semiconductor integrated circuit devices are built in a silicon wafer etc., then are diced, bonded, packaged, and otherwise processed to form finished electronic devices. These IC devices are subjected to operational tests before shipment. These IC tests are run in the state of the finished products and in the state of the wafer.
When testing an IC device in the wafer state, probe needles (hereinafter also referred to as “contactors”) provided on a probe card of the electronic device test apparatus are brought into contact with the IC device to establish an electrical connection with the IC device. The contactors are required to be provided with conductivity and elasticity for destroying the oxide film formed on the input/output terminals of the IC device to secure electrical contact.
As such a contactor, a silicon finger contactor comprises: beam parts made of silicon (Si) with rear end sides provided at a base part and with front end sides sticking out from the base part; and nickel-cobalt layers formed at the surfaces of the beam parts has been known in the past (for example, see Patent Literatures 1 to 3).
In this silicon finger contactor, the nickel-cobalt layers are used to secure the electrical connection with input/output terminals of the IC device and secure the majority of the elasticity of the contactor. However, nickel-cobalt is a metal material, so repeated contact with input/output terminals of an IC device results in plastic deformation. When such plastic deformation accumulates, the height of the front end part of the contactor (contact part) from a surface of the probe card becomes lower. For this reason, along with repeated tests, the contact state between the IC device and the contactor changes and it is impossible to perform accurate tests in some cases.
Further, the nickel-cobalt layers expand due to heat by the effects of the thermal stress applied to the IC device at the time of testing, so the difference in heat expansion from the silicon composing the beam parts causes warping in the silicon finger contactor and deviation in the height of the front end parts contacting the IC device with respect to the IC device in some cases.
Patent Literature 1: Japanese Patent Publication (A) No. 2000-249722
Patent Literature 2: Japanese Patent Publication (A) No. 2001-159642
Patent Literature 3: International Publication No. 03/071289 pamphlet